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Gum Tragacanth (long)

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  • Jake Benson
    Gum tragacanth is a highly variable creature. It is our common name for approximately 20 varieties astragalus that produce a gum, generally grouped under the
    Message 1 of 1 , Aug 29 6:07 PM
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      Gum tragacanth is a highly variable creature. It is our common name for
      approximately 20 varieties astragalus that produce a gum, generally grouped
      under the term tragacantha. The Tragacanth used historically came to Europe
      from the port of Izmir (formerly Smyrna) in Turkey, hence the reference in
      Josef Halfer's book (The Progress of the Marbling Art, Budapest 1884,
      translated by Herman Dieck, and republished by the Fresh Ink Press in 1991 (?)
      and the Garland Press 1990) to "Smyrna leaf is the best". Other types were
      produced around the North Eastern Mediterranean, Middle East, and Asia.

      The plant is incised on the stem near the root. The method of incision is
      similar to the manner used in Opium production. Small lateral cuts are made
      with a knife, piece of glass or a rough shell. The gum exudes through the
      slit, and dries, forming irregularly twisting ribbons. This is what is
      referred to by Halfer as "leaf" tragacanth. He also describes the appearance
      of the gum as "irregular flattened shapes and in tortuous vermicular
      filaments". I love the latter part of that description! Halfer has
      undoubtedly some of the most interesting comments about Tragacanth in all of
      marbling literature, the result of so many years of intense work. He even
      mentions how when using earth colors with tragacanth, that alum mordanting is
      unnecessary, which happens to be the prevalent practice in Turkey. His
      section on Tragacanth is often overlooked, I think because of his discovering
      a method of preserving Carragheen Moss and advocating it's use, to the
      eventual detriment of gum tragacanth.

      Still, there are those marblers who feel using a gum mucilage for marbling
      can be advantageous for certain particular reasons. Historically and still
      today, in some American and European bookbinderies, the marbling of text block
      edges would be done on a regular basis. The marbling tank and colors would be
      left out to be used when necessary over longer periods of time. The patterns
      used on marbled edges were for the most part basic patterns, spots and combs.
      The short life of the carragheen size together with a need for marbling a
      small item, often in simple patterns led to its' disfavor, for the particular
      marbling of edges. Gum sizes can last substantially longer. Many Turkish
      marblers have told me they can use their bath up to 3 months sometimes,
      usually in the winter.

      John Mitchell (now retired gold finisher to the Queen Elizabeth), in his
      recent book on Edge Decoration covers the topic of edge marbling, giving
      instructions for using carragheen, tragacanth, linseed, flea seed, and flax,
      and then goes on to give directions for using "Robin's traditional starch".
      When the book was reviewed by someone in the Guild of Book workers Newsletter,
      the reviewer blasted Mr. Mitchell for including these other methods, saying
      among many things, that "most marblers use carragheen today". I felt when I
      read the review that the author was oblivious and very naive as to the
      economy, practicality, and even a quite a lot of history that lay behind Mr.
      Mitchell's particular recommendations.

      Most of us are quite well versed in the virtues of Carragheen, thanks to
      the original efforts made by Halfer. While Halfer advocated the use of
      Carragheen for edge marbling, Louis Kinder, a master german binder who worked
      at the Roycroft Bindery (and the publisher of the English translation of
      Halfer's book), offered a variety of gum recipes for the purpose in his
      Formulas for Bookbinders. He even experimented with trying to mix various
      gums. I've done a little of that- nothing was succesful that I tried, but
      what resulted was really wierd and freaky ("ropy" strands of mucilage forming,
      different gums having a phobia of each other and refusing to mix, even when
      stirred, macerated, blended, and left to rot( a whole soap opera)!!

      Halfer instructions are very similar to what is practiced today in Turkey.
      He says "take 3 ounces of tragacanth, pour two quarts water over it, leave it
      stand for 24 hours, then stir well and leave it standing for 12 hours more,
      repeat this until the homogenous thick mucilage has been produced, then add 4
      quarts of water , again stir it up well and filter it and the size is ready
      for the marbling process". Elsewhere he suggests boiling the mucilage after 1
      or 2 days" to produce a more homogenous size, similar to carragheen". Kinder
      also recommends boiling.

      In general the Turks don't boil, but they usually have very fresh stuff to
      work with. This is a very critical factor for success for using the gum in
      general. I have never seen the leaf or ribbon trag available here. Most of
      what comes from suppliers here is quite old. As translucent white trag ages,
      it turns yellow then a hard, opaque tannish brown. If the trag was powdered,
      it ages even more poorly. Purified forms usually won't be able to form a
      mucilage either, as the complex molecular chains of dextrin etc., are broken
      up.

      I have tried a lot of powdered varieties available here, and none of it has
      worked well. I have tried many sorts of inferior ribbon and leaf trags from
      Iran and India that also yielded a poorer size that would never get quite
      homogenous. Only that beautiful fresh sparkling Turkish stuff really works
      well enough to bother with. Then again, maybe my expectations of what a good
      size trag can yield is biased by my association with the Turkish folks who use
      that high quality stuff.

      Unfortunately, even this is harder to get today in Istanbul. I was given
      various possible reasons for this, ranging from "no one wants to do the work
      of collecting it" to "the PKK terrorists are shooting the people who try to
      collect it" I really didn't have time to get to the bottom of it, but in
      general, all the spice shops in Istanbul had only inferior grade trag available.

      This last year I did find some very nice looking stuff in Egypt that I
      assumed may come from Turkey, despite the fact the guy selling it said it was
      "African", giving no particular place of origin (and our mutual presence in
      Africa!). I made a mucilage and did some very rough marbling with some
      pigments from the local market as a test. I gave some to one friend who
      didn't like it, and haven't had a chance to test it yet since. Maybe I will
      when the cold weather comes.

      Jake Benson
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